As a show, Firefly does lots of things. It makes you laugh, cheer, cry, go out and buy a long brown duster and pick fights on Unification Day. But every now and again, Firefly also makes you scared. And not with gooey make-up or “boo-something’s-in-the-mirror” camera gooses. Just with a man, the bounty hunter Jubal Early, making his intentions crystal clear.